• E
    userns: Don't fail follow_automount based on s_user_ns · bbc3e471
    Eric W. Biederman 提交于
    When vfs_submount was added the test to limit automounts from
    filesystems that with s_user_ns != &init_user_ns accidentially left
    in follow_automount.  The test was never about any security concerns
    and was always about how do we implement this for filesystems whose
    s_user_ns != &init_user_ns.
    
    At the moment this check makes no difference as there are no
    filesystems that both set FS_USERNS_MOUNT and implement d_automount.
    
    Remove this check now while I am thinking about it so there will not
    be odd booby traps for someone who does want to make this combination
    work.
    
    vfs_submount still needs improvements to allow this combination to work,
    and vfs_submount contains a check that presents a warning.
    
    The autofs4 filesystem could be modified to set FS_USERNS_MOUNT and it would
    need not work on this code path, as userspace performs the mounts.
    
    Fixes: 93faccbb ("fs: Better permission checking for submounts")
    Fixes: aeaa4a79 ("fs: Call d_automount with the filesystems creds")
    Acked-by: NIan Kent <raven@themaw.net>
    Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
    bbc3e471
namei.c 121.0 KB